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From lars hofhansl <la...@apache.org>
Subject Re: coprocessor enabled put very slow, help please~~~
Date Mon, 18 Feb 2013 02:31:20 GMT
The main advantage of coprocessors is that they keep the logic local to the region server.
Putting data into other region servers is supported, but defeats the performance purpose.



________________________________
 From: Prakash Kadel <prakash.kadel@gmail.com>
To: "user@hbase.apache.org" <user@hbase.apache.org> 
Sent: Sunday, February 17, 2013 5:26 PM
Subject: Re: coprocessor enabled put very slow, help please~~~
 
thanks again,
  i did try making indexes with the MR. dont have exact evaluation data, but inserting indexes
directly with mapreduce does seem to be much much faster than making the indexes with the
coprocessors. guess i am missing the point about the coprosessors. 
my reason for trying out the coprocessor was to make the insertion code cleaner and efficient
index creation.

Sincerely,
Prakash Kadel

On Feb 18, 2013, at 10:17 AM, lars hofhansl <larsh@apache.org> wrote:

> Index maintenance will always be slower. An interesting comparison would be to also update
your indexes from the M/R and see whether that performs better.
> 
> 
> 
> ________________________________
> From: Prakash Kadel <prakash.kadel@gmail.com>
> To: "user@hbase.apache.org" <user@hbase.apache.org> 
> Sent: Sunday, February 17, 2013 5:13 PM
> Subject: Re: coprocessor enabled put very slow, help please~~~
> 
> thank you lars,
> That is my guess too. I am confused, isnt that something that cannot be controlled. Is
this approach of creating some kind of index wrong?
> 
> Sincerely,
> Prakash Kadel
> 
> On Feb 18, 2013, at 10:07 AM, lars hofhansl <larsh@apache.org> wrote:
> 
>> Presumably the coprocessor issues Puts to another region server in most cases, that
could explain it being (much) slower.
>> 
>> 
>> 
>> ________________________________
>> From: Prakash Kadel <prakash.kadel@gmail.com>
>> To: "user@hbase.apache.org" <user@hbase.apache.org> 
>> Sent: Sunday, February 17, 2013 4:52 PM
>> Subject: Re: coprocessor enabled put very slow, help please~~~
>> 
>> Forgot to mention. I am using 0.92.
>> 
>> Sincerely,
>> Prakash
>> 
>> On Feb 18, 2013, at 9:48 AM, Prakash Kadel <prakash.kadel@gmail.com> wrote:
>> 
>>> hi,
>>>     i am trying to insert few million documents to hbase with mapreduce. To
enable quick search of docs i want to have some indexes, so i tried to use the coprocessors,
but they are slowing down my inserts. Arent the coprocessors not supposed to increase the
latency? 
>>> my settings:
>>>      3 region servers
>>>     60 maps
>>> each map inserts to doc table.(checkAndPut)
>>> regionobserver coprocessor does a postCheckAndPut and inserts some rows to a
index table.
>>> 
>>> 
>>> Sincerely,
>>> Prakash
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